This invention relates to a machining tool with grinding function equipped with an electric discharge truing/ dressing apparatus of a metal bond grinding wheel for grinding a workpiece.
And, this invention relates to a machine tool having grinding function capable of performing a center work machining and the like and capable of dressing in state that a tool for grinding is installed in a tool rest, a dressing apparatus being used for it and the dressing method, and grinding tool.
Furthermore, this invention relates to a chip collecting apparatus using for a machine tool such as a lathe and its collecting method.
In recent years, ceramic materials or the like have caught much attention because of their characteristics such as resistance to high temperature and resistance to wear, and have been applied to various kinds of devices. Therefore, developments and proposals have been made on machining art or technique so that ceramic materials can be cut and/or ground as easily as iron materials can. The present inventors have tried to grind a hard and fragile material using a cast iron bond diamond grinding wheel and a machining center. As a result, they have confirmed that the high efficient machining of ceramics and cemented carbide or sintered hard alloy was effective.
In order to perform the grinding machining by a cast iron bond diamond grinding wheel with high accuracy and efficiency, however, truing/dressing is indispensable on the body of a machining tool. Heretofore, it was said that no effective truing/dressing methods were present with respect to a metal bond grinding wheel. The present inventors have proposed a wire electric discharge truing/dressing method on the body of a machining tool.
The illustrations of FIGS. 4 and 5 show the principle thereof, in which an electric discharge machining is performed between a wire electrode 95 and a metal bond grinding wheel 90 using a wire cut electric discharge power source 96. Since electric discharge truing/dressing is performed on the body of a machining tool, there can be obtained a high accuracy with least errors. The present inventors have proposed a turing center in which the afore-mentioned dressing method was applied.
Furthermore, the present inventors have proposed an electric discharge truing by a block-like electrode as an improvement of an electric discharge truing/dressing method by the afore-mentioned wire electric discharge. The present inventors also have proposed a method for performing an electric discharge truing/dressing of a metal bond grinding wheel mounted on a tool spindle using a generated electrode obtained by cutting an electrode into a desired configuration by a tool mounted on a tool spindle.
However, since the machining by the wire electric electrode was required the use of a wire electrode, the electric discharge was partially taken place and an average electric current was limited. Therefore, the removing efficiency of the metal portion of the metal bond grinding wheel became insufficient and the truing/dressing efficiency became worse. In addition, since the wire was limited in thickness, the shape truing of the grinding wheel was limited in configuration. For example, there arised such a problem in that an irregularity having a sharp angle or a complexed configuration could not be generated.
The proposals of the electric discharge truing by the block-like electrode were all no more than the proposals of the principle of the electric discharge truing/dressing method. The proposals were still insufficient in solving the problems relating to the structure and arrangement of the truing/dressing apparatus, particularly in the respect that they were applied to a turning center for grinding machining a cylindrical workpiece with high efficiency. That is, in the conventional special machining such as electro-chemical machining, one-to-one automatic machining was available but there was no such machine in which workpieces W having various configurations could be continuously machined without manpower. Therefore, in the prior art, it was impossible to attain automation by saving manpower, etc.
And, heretofore, the proposal is advanced relating a dressing apparatus by which truing and the like are performed by means of electric discharge machining toward the grinding stone portion which is blinded. In prior art, in order to perform truing and the like by means of the dressing apparatus, rough turing and dressing are perfomed toward the grinding stone portion which is blinded by using a machining electrode for rough machining at first. Thereafter, the machining electrode for rough machining is detached from the dressing apparatus and the machining electrode for finishing machining is attached to it in return. In this way, the finishing truing and dressing are performed.
However, in this method, it is necessary that the machining electrode for rough machining is detached after rough truing toward the grinding stone portion of a grinding tool and the machining electrode for finishing machining is attached. And, it is inconvenient that finishing truing and the like can't be performed immediately.
To realize the attempt needs the development of the art. That is, it is that electricity is fed to a grinding stone portion via the electrode by connecting the electrode with the grinding stone portion being free to connect and separate. But, such an art is far from development.
Moreover, in the prior art, when a center work machining and the like are performed by means of a complex machining machine tool, one edge portion of a workpiece is held by the spindle of the machine tool via a chuck, and the other edge portion is supported by the center of a tailstock. In this state, a workpiece is cut at the predetermined form by the tool being installed in a tool rest.
In recent years, the proposal, to perform grinding machining toward a workpiece by installing the tool for grinding in a tool rest in a complex machining machine tool, is advanced. But, in case that the blinding rises in a grinding tool, it is necessary to perform dressing. Then, the method in which dressing is performed by electric discharge machining toward the grinding stone which is blinded is adopted in the prior art. On this occasion, dressing is performed in such a manner that the tool for grinding which is blinded is detached from the tool rest and is attached to an electrical discharge machine being provided in the shape of being separated from the complex machining machine tool.
However, according to this method, a worker must perform the operations of the detachment and attachment of a grinding tool whenever dressing is performed. And, it is difficult to perform grinding activity automatically without manpower in the complex machining machine tool. Then, it is thinkable that a dressing apparatus is disposed on the machine body of the complex machining machine tool and dressing is performed in the state that the grinding tool is installed in the tool rest by means of the apparatus. In this method, the new problem occurs. That is, there is a case that the machining can't be performed because of the interference between the tailstock which is provided being free to move on the machine body in the same manner as the dressing apparatus and the dressing apparatus, when center workpiece machining and the like is performed.
In the conventional machine tool such as a lathe, when the machining is performed toward workpieces in the different kind of material, differentiation of machining isn't present except for specific case. Therefore, the chip produced is collected in the shape of mixing different kind of chip.
This method is defective in complication of separation and classification operations of chip for the object in which resource is effectively utilized. In case that the workpiece which is different completely in character such as metal and ceramics is machined, the chip collecting apparatus capable of collecting in the shape of classifying the chip produced from first is desirable.
It is therefore an object of the present invention to provide an electric discharge truing/dressing apparatus suitably used for a turning center in which electric discharge truing/dressing of a metal bond grinding wheel is performed on the body of a machining tool.
Another object of the present invention is to provide a machining tool with a grinding function, in which an electrode is automatically exchanged in order to perform the electric discharge truing/dressing of a metal bond grinding wheel of a turning center on the machine body, thereby to attain a long time driving without manpower.
A further object of the present invention is to provide a machining tool with a grinding function, in which an electrode is disposed on a workpiece spindle stock so that electric discharge truing/dressing of a metal bond grinding wheel of a turning center is performed on the machine body.
A still further object of the present invention is to provide an electric discharge truing/dressing apparatus which can sufficiently cope with thermal displacement of a spindle stock by mounting an electrode on the spindle stock of a turning center.
A yet further object of the present invention is to provide a most suitable constitution of a CNC machining tool with an electric discharge truing/dressing apparatus and more particularly to provide a machining tool, in which an electrode machining tool and a grinding wheel are mounted on a tool rest so that a plural kinds of workpieces can be machined.
And, it is an object of the present invention to provide a truing/dressing apparatus capable of improving machining efficiency in such a manner that rough truing and dressing is performed toward the grinding stone portion of the grinding tool, and thereafter finishing truing and dressing is performed immediately without reattaching the electrode, in order to eliminate the above-described defects.
Moreover, it is an object of the present invention to provide the grinding tool capable of installing in a machine tool and capable of perform truing and dressing in such a manner that electric discharge machining is performed toward the grinding stone portion in state that the electrode is certainly connected with the grinding stone portion being free to connect and separate.
And, it is an object of the present invention to provide the machine tool with a dressing apparatus capable of performing center workpiece machining and the like and capable of performing dressing in state that a grinding tool is installed in the tool rest.
Furthermore, it is an object of the present invention to provide the chip collecting apparatus capable of classifying and stocking the chip produced easily if the material to be machined changes.